Multi-pack disposable shaving razors are a popular low cost option for shaving needs. Each disposable razor can typically be used several times before it is discarded.
In some instances, multiple users each have a disposable razor and share a bathroom. For hygiene and other purposes it is desirable that razors not be shared. For example, razor blades can spread infections such as warts, which are caused by a virus, folliculitis, which is typically caused by staph bacteria, or jock itch, which is a fungal infection. This is because shaving creates microscopic openings in the skin, which allow organisms to enter and spread infection. And, although they're usually spread by direct contact, the viruses that cause herpes and hepatitis can also linger on razor blades or in the moist areas between blades.
There is also less risk of nicks or dry, flaky skin—if a sharp razor is used to “skim” the skin instead of tugging against it. A general rule of thumb is to replace the razor after a certain number of uses and this can be tracked more easily if the razor is not shared.
It is also desirable to store the razor in a dry and hygienic environment to prevent or reduce the growth of organisms on the blade. Keeping the razor from sitting in pooled water may also extend the life of the blades by slowing down oxidation (rust) on blades and prevent the lubricating strip from getting soaked and/or from sticking to bathroom surfaces.